Noun: The nickname given to followers of Scientology (Scientologists). Often used in the City of Clearwater, Florida, which is the "spiritual headquarters" of Scientology. Considered to be insultive by Sci-Fis themselves.

1. A bunch of Sci-Fis just moved in next door...they're taking over the neighborhood.
2. Traffic on Ft. Harrison wouldn't be so bad if it weren't for the hundreds of Sci-Fis trying to cross the street.